The present invention relates to an assembly for opening/closing molds of a glassware molding machine.
In glassware molding, molding machines, known as I.S. machines, are used, which comprise a number of side by side forming sections, each for producing a succession of products.
Each forming section comprises a rough mold normally comprising a row of side by side cavities, each for receiving a glass gob and forming a respective semifinished product. Each semifinished product is fed in a forming direction and transferred by an inverter to a finish mold, in which the semifinished product is processed further to obtain the desired finished product, which is then ejected from the mold and carried off.
The rough mold and finish mold each comprise two half-molds movable with respect to each other between a closed position and an open position.
The half-molds are moved between the open and closed positions by a mold opening/closing assembly comprising, for each mold, two actuating arms, which are fitted to respective half-molds and hinged to a fixed structure to rotate, under control of a mechanical transmission, in opposite directions about vertical axes. The transmission is operated by a single linear actuator, the translating output member of which moves back and forth in a direction perpendicular to the fixed vertical hinge axes.
Though widely used in conventional forming sections, known mold opening/closing assemblies of the above type are practically impossible to install on new-generation forming sections, mainly on account of their bulk in the forming direction. This is substantially due to the type of transmissions employed, and the location of the actuator, which must be located as close as possible to the molds to minimize inevitable slack in the linkage connecting the actuator to the arms.
The bulk of the opening/closing assembly in the forming direction also poses a wide range of problems when dismantling the assembly from the section, e.g. for routine overhauling or repair, which also involves removing other parts of the section.
Some of the above problems have been partly solved using actuators with vertical translating output members, and dedicated mechanical transmissions.
Mold opening/closing assemblies of this sort, however, have other drawbacks of their own, and more specifically a large number of moving parts. The inevitable friction involved seriously, and at times unpredictably, affects the movement of the half-molds, particularly the dead centre positions, thus resulting in a mold opening/closing assembly that is difficult to control—by failing to ensure correct proportion and timing between the thrust exerted by the actuator and the movement of the arms—and in the production of substandard glass articles in terms of shape and quality.